Body fluid pressure indicator and regulator and method for continuously regulating and monitoring the pressure of a body fluid

Abstract

Apparatus and method are disclosed for indicating and regulating the pressure of a selected body fluid such as an intracranial fluid. An elongated indicator tube is carried at least in part in a vented chamber which can be mounted so that the indicator tube is in a substantially vertical position. A flexible conduit conveys the selected body fluid from a catheter in the patient to the lower end of the indicator tube. By positioning the indicator tube so that the lower end is level with the in-dwelling end of the catheter, the extent of travel of the body fluid along the tube is a direct indication of the pressure of the body fluid. To provide an upper limit on the pressure the body fluid may attain, at least one opening is provided at a selected position in the wall of the indicator tube inside the chamber. This opening provides an upper pressure limit by permitting fluid to escape from the indicator tube into the chamber when the pressure is sufficient to cause the fluid to reach the opening. The chamber is vented so that compressed air inside the chamber does not affect the fluid pressure reading, and the extent of travel of the fluid inside the indicator tube represents the true pressure of the body fluid. Drainage means is provided for draining the chamber of any body fluid forced thereinto and the flexible conduit has an access port between the indicator tube and the catheter for sampling fluid or for injecting medicament.

That which is claimed is: 
     
       1. A body fluid pressure indicator and regulator comprising: walls defining an internal chamber, vent opening means in said chamber to continuously vent said chamber to the ambient so that said chamber is always at ambient pressure while maintaining said chamber contamination free, elongated indicator means carried at least in part within said chamber, conveying means for continuously conveying body fluid between its source in the body of a patient and said indicator means without any valve means through said indicator means having its lower end communicating continuously with said conveying means so that the body fluid is conducted into said indicator means when the pressure of the body fluid increases and out of said indicator means when the pressure of the body fluid decreases and is below a maximum desired pressure, the distance the body fluid extends along said indicator means representing the pressure of said fluid, said indicator means having its upper end terminating in said chamber, and said indicator means having pressure limiting opening means interior of said chamber and spaced a selected, fixed distance above said lower end of said indicator means in accordance with the maximum desired pressure of the body fluid, said pressure limiting opening means providing an upper limit to the body fluid pressure by permitting escape of the fluid from said indicator means into said chamber when the pressure of the body fluid exceeds its maximum desired pressure to regulate the pressure of the body fluid. 
     
     
       2. A body fluid pressure indicator and regulator in accordance with claim 1 in which said conveying means comprises a flexible tube, body communicating means to communicate with the source of body fluid in the patient to receive the body fluid, and one end of said flexible tube communicating with said lower end of said indicator means and the other end of said flexible tube communicating with said body communicating means. 
     
     
       3. A body fluid pressure indicator and regulator in accordance with claim 2 in which access port means is provided intermediate of said ends of said tube. 
     
     
       4. A body fluid pressure indicator and regulator in accordance with claim 1 which includes drainage opening means in said chamber for draining body fluid therefrom, and drain valve means carried by said drainage opening means for controlling the flow of fluid therethrough. 
     
     
       5. A body fluid pressure indicator and regulator in accordance with claim 1 which includes sterile barrier filter means in cooperative association with said vent opening means for restricting the admission of harmful material into said chamber. 
     
     
       6. A body fluid pressure indicator and regulator comprising: housing means including both a hollow transparent barrel disposable in a substantially vertically extending position and closure means closing upper and lower ends of said barrel, vent opening means in said housing means located above the lower end of said barrel and communicating with the interior thereof to continuously vent the inside of said barrel to the ambient so that the inside of said barrel is always at ambient pressure, filter means cooperatively associated with said vent opening means to restrict admission of harmful matter into said barrel so that the inside of said barrel is contamination free, a transparent elongated indicator tube carried at least in part in said barrel and being generally parallel thereto for disposition in a substantially vertical position, means for continuously conveying body fluid between the lower end of said indicator tube and a patient without any valve means whereby body fluid is conducted directly into said indicator tube when the pressure of the fluid in the body increases with the vertical distance the fluid extends therealong indicating the pressure of the fluid and the body fluid is returned to the body from said indicator tube when the pressure of the fluid in the body decreases and is below a maximum desired pressure, the upper end of said indicator tube terminating within said barrel at a level above the lower end of said barrel, and pressure limit opening means in the portion of said indicator tube located within said barrel at a selected, fixed distance in accordance with the maximum desired pressure of the body fluid, said pressure limit opening means providing an upper limit to fluid pressure of the body fluid by permitting the body fluid to flow from said indicator tube into the area between said indicator tube and the inside of said barrel if said fluid reaches said pressure limit opening means due to the pressure of the body fluid exceeding its maximum desired pressure. 
     
     
       7. An indicator and regulator in accordance with claim 6 in which calibration means is provided along said indicator tube for indicating the pressure of said fluid. 
     
     
       8. An indicator and regulator in accordance with claim 6 in which the closure means closing the lower end of said barrel includes a drain opening means communicating between said indicator tube and the inside of said barrel and valve means resistant to the transmission of bacteria carried by said drain opening means for controlling the flow of fluid therefrom. 
     
     
       9. An indicator and regulator in accordance with claim 6 in which said conveying means comprising a flexible tube communicating at one end with the lower end of said indicator tube and communicable at the other end with the patient. 
     
     
       10. An indicator and regulator in accordance with claim 9 in which said flexible tube includes an access port intermediate of said ends of said flexible tube. 
     
     
       11. An intracranial fluid pressure indicator and regulator comprising: a hollow transparent barrel,   mounting means associated with said barrel for mounting in a vertical position,   upper and lower end caps closing each end of said barrel,   vent opening means in said upper cap for continuously venting the inside of said barrel to the ambient to maintain the inside of said barrel at ambient pressure,   filter means carried on said upper cap adjacent said vent opening means to restrict admission of harmful matter into said barrel through said vent opening means to maintain the inside of said barrel contamination free,   fluid opening means in said lower end cap for receiving body fluid,   an elongated, transparent indicator tube completely enclosed within said barrel and extending generally parallel to the axis of said barrel, said indicator tube having its lower end supported by said lower end cap,   body communicating means insertable into a patient,   a fluid conveying tube exterior of said barrel terminating at one end of said fluid opening means in said lower cap and terminating at the other end with said body communicating means, said flexible tubing having a fluid access port between said ends thereof,   the lower end of said indicator tube continuously communicating with said fluid opening means in said lower cap so that intracranial fluid may be continuously communicated between the patient and said indicator tube with the fluid flowing into said indicator tube when the pressure of the fluid in the patient increases and returning to the patient from said indicator tube when the pressure of the fluid in the patient decreases and is below a maximum desired pressure, the vertical travel of the fluid in said indicator tube representing the pressure of the intracranial fluid of the patient,   drain valve means in said lower cap communicating between said indicator tube and the inside of said barrel for selectively draining fluid from between said indicator tube and the inside of said barrel while preventing contamination of the inside of said barrel,   and pressure limiting opening means in said indicator tube spaced a selected, fixed distance from the lower end of said indicator tube in accordance with the maximum desired pressure of the intracranial fluid whereby the intracranial fluid reaching said pressure limiting opening means will flow into the space between said indicator tube and the inside of said barrel to relieve the pressure of the intracranial fluid until it decreases to the maximum desired pressure so that the pressure of the intracranial fluid is regulated.   
     
     
       12. The intracranial fluid pressure indicator and regulator of claim 11 in which: said indicator tube has its upper end supported by said upper end cap,   and said pressure limiting opening means comprises at least one opening located at a selected distance above the lower end of said indicator tube in accordance with the maximum desired pressure of the intracranial fluid, said opening being below the upper end of said indicator tube.   
     
     
       13. A method of continuously regulating and monitoring the pressure of a body fluid of a patient including: providing communication without any valve means between a source of body fluid in a patient and an elongated indicator means having a relatively small constant cross sectional area in its portion in which the pressure of the body fluid is indicated so as to be monitored and disposed at least partially within a contamination free chamber;   continuously maintaining the chamber at ambient pressure;   disposing the elongated indicator means relative to the source of the body fluid so that the level of the body fluid in the elongated indicator means continuously indicates the pressure of the body fluid in the patient whereby the pressure of the body fluid can be continuously monitored until it reaches a maximum desired pressure;   regulating the pressure of the body fluid in the patient through relieving the pressure of the body fluid in the patient when it exceeds the maximum desired pressure by channelling fluid due to the pressure of the body fluid exceeding the maximum desired pressure from the elongated indicator means into the chamber until the pressure of the body fluid does not exceed the maximum desired pressure;   and allowing the return of body fluid to the patient only from the elongated indicator means when the pressure of the body fluid decreases and the pressure is below the maximum desired pressure.   
     
     
       14. The method according to claim 13 including disposing the elongated indicator means in a substantially vertical position. 
     
     
       15. The method according to claim 14 including draining the body fluid from the chamber without causing any contamination of the chamber and prior to the level of the body fluid in the chamber reaching a level at which it can flow into the elongated indicator means.